Continuously variable transmission

Abstract

The invention relates to drive devices in which the speed and direction of rotation of an output shaft can be continuously varied. A continuously variable transmission comprises a primary shaft, a variator, a three-link planetary gear, and an output shaft. The variator consists of a drive pulley and a driven pulley which are coupled by a belt. The continuously variable transmission further comprises a frictional toothed clutch configured to be capable of coupling and uncoupling the primary shaft and a first pinion that is coupled to a first and a second gear. The continuously variable transmission still further comprises a toothed clutch configured to be capable of coupling and uncoupling the drive pulley of the variator and the second gear. The first gear is coupled to the carrier of the planetary gear. The annulus of the planetary gear is coupled to the driven pulley of the variator, and the planet gears of the planetary gear are coupled to the sun gear, which is coupled to the following serially coupled elements: the output shaft, a second pinion, and a third gear. The result is that of simplifying the structure of the continuously variable transmission and increasing the reliability thereof.

Description

[0001] Continuously variable transmission

[0002] Field of technology

[0003] The invention relates to mechanical engineering, namely to drive devices with stepless change of speed and direction of rotation of the output shaft, and can be used in ground transport equipment.

[0004] State of the art

[0005] A continuously variable transmission is known, disclosed in the Russian Federation patent for invention No. 2656941 (published on 07.06.2018, IPC F16H 15 / 50). The continuously variable transmission comprises a friction variator and a simple three-link planetary mechanism consisting of a sun gear, an epicyclic wheel and a planet carrier with satellites. The input and output shafts are installed in parallel, a toothed ring with a clutch for engaging the leading cylindrical gear, which is freely installed on the input shaft and meshed with the driven cylindrical wheel fixed to the epicyclic wheel housing. A clutch for locking the planetary mechanism or stopping the epicyclic wheel is installed on the toothed ring of the tubular shaft of the housing. The small friction wheel is mounted on the key of the input shaft, pressed against the large friction wheel of the driven shaft, which is connected to the sun gear by a bevel gear and a shaft. The carrier is fixed to the output shaft.The toothed rim of this shaft is located next to the toothed rims of the tubular shaft of the epicyclic gear housing and the continuously variable transmission housing.

[0006] A drive device is known, disclosed in the Russian Federation patent for invention No. 2748081 (published on 19.05.2021, IPC F16H 37 / 08). The known drive device comprises a differential at the input, a planetary gear at the output, the carrier of which is made integral with the output shaft of the device, and a V-belt variator connected to the differential and the planetary gear via gears. The revolutions of the differential axle shafts are changed by changing the gear ratio of the variator and are separately fed to the sun and ring gears of the planetary gear. One of the flows is fed in the opposite direction of rotation. The revolutions of the sun and ring gears are differentially dependent. The axes of the satellites are carried away by the total rotation speed of the sun and ring gears in the direction of rotation of the input shaft or in the opposite direction with a transition through "zero". The continuously variable transmission Jatco JF015E is known as a prototype.The well-known continuously variable transmission Jatco JF015E is characterized by a sequential arrangement of the torque converter, a package (gear block) of the front and reverse gears, a variator and a two-stage reducer with a built-in interwheel differential. The disadvantage of this variator box is the presence of a torque converter, a package (gear block) of the front and reverse gears in the design, as well as a limited operational mileage of 200 ... 220 thousand kilometers. This is due to belt stretching, wear of the belt and the working surfaces of the variator pulleys. The Jatco JF015E variator box model is installed on passenger cars of Nissan, Mitsubishi, Chevrolet, Daewoo and other factories.

[0007] Disclosure of the essence of the invention

[0008] The technical problem underlying the present invention is to expand the range of V-belt continuously variable transmissions.

[0009] The technical result achieved by implementing the present invention consists in increasing the operating mileage of a V-belt continuously variable transmission.

[0010] Additional technical results include simplification of the continuously variable transmission design and increased reliability.

[0011] The technical result is achieved by the present invention, which proposes a continuously variable transmission. The proposed continuously variable transmission includes a primary shaft, a variator, which consists of a driving pulley and a driven pulley connected by a belt, a three-link planetary mechanism, which consists of a carrier with satellites, an epicycle and a sun gear, and an output shaft.Unlike the prototype, the proposed continuously variable transmission additionally includes a friction-tooth clutch, which is designed with the ability to connect and disconnect the primary shaft and the first gear connected to the first and second gear wheels, a toothed clutch, which is designed with the ability to connect and disconnect the driving pulley of the said variator and the second gear wheel, wherein the first gear wheel is connected to the carrier of the said planetary mechanism, wherein the epicycle of the said planetary mechanism is connected to the driven pulley of the said variator, and the satellites of the said planetary mechanism are connected to the sun gear, which is connected to the sequentially connected output shaft, the second gear wheel and the third gear wheel. Brief description of the drawings.

[0012] The present invention is illustrated by the following drawings:

[0013] - FIG. 1 shows the kinematic diagram of a continuously variable transmission;

[0014] - FIG. 2 shows the first diagram of the variator;

[0015] - FIG. 3 shows the second diagram of the variator;

[0016] - FIG. 4 shows the third variator diagram.

[0017] The following symbols are used in the drawings:

[0018] 1 - primary shaft;

[0019] 2 - friction-tooth clutch;

[0020] 3 - first gear;

[0021] 4 - first gear wheel;

[0022] 5 - second gear wheel;

[0023] 6 - leading pulley;

[0024] 7 - driven pulley;

[0025] 8 - belt;

[0026] 9 - driver;

[0027] 10 - axles;

[0028] 11 - satellites;

[0029] 12 - sun gear;

[0030] 13 - shaft;

[0031] 14 - second gear;

[0032] 15 - third gear:

[0033] 16 - coupling;

[0034] 17 - epicycle;

[0035] 18 - crankshaft;

[0036] 19 - internal combustion engine;

[0037] 20 - drive wheels;

[0038] 21 - case

[0039] 22 - interwheel differential.

[0040] Description of embodiments of the invention

[0041] FIG. 1 shows a kinematic diagram of a continuously variable transmission. In accordance with the shown kinematic diagram, the primary shaft 1 of the continuously variable transmission is connected to the friction-tooth clutch 2 and the first gear 3 located on the same axis. The friction-tooth clutch is designed with the possibility of connecting and disconnecting the primary shaft 1 and the first gear 3. The first gear 3 is engaged with the first gear wheel 4 and the second gear wheel 5.

[0042] The variator consists of a driving pulley 6 and a driven pulley 7, which are connected to each other by a belt 8.

[0043] The first gear wheel 4 is connected to the carrier 9 of the three-link planetary mechanism located on the same axis. Satellites 11 are mounted on the axes 10 of the carrier 9. Satellites 11 are engaged with the sun gear 12, which is connected to the sequentially connected output shaft 13, the second gear 14 and the third gear wheel 15.

[0044] The second gear wheel 5 is connected to the clutch 16, which is designed to connect and disconnect the second gear wheel 5 and the leading pulley 6 of the variator. The driven pulley 7 of the variator is connected to the epicycle 17. The epicycle 17 is engaged with the satellites 11.

[0045] The primary shaft 1 is connected to the crankshaft 18 of the internal combustion engine 19. The third gear wheel 15 is connected to the drive wheels 20 via the interwheel differential 22.

[0046] The continuously variable transmission is assembled in housing 21.

[0047] The rotation speed of gear wheel 15, equal to the rotation speed of drive wheels 20, is determined by the formula: where П] is the rotation frequency of the primary shaft 1, equal to the rotation frequency of the crankshaft 18, rpm;

[0048] •У d - gear ratio of the planetary stage with stopped sun gear 12.

[0049] The gear ratio of the planetary mechanism is determined by the following formula: where Zi2 is the number of teeth of the sun gear 12; zn ~ the number of teeth of the epicycle 17; is is the gear ratio of the gear pair of the first gear 3 and the first gear wheel 4.

[0050] The gear ratio of gear pairs 3 and 4 is determined by the following formula: where Z3 is the number of teeth of gear 3;

[0051] Z4 - number of teeth of the first gear wheel 4; ii - variable gear ratio of the variator.

[0052] The variable gear ratio of the variator is determined by the following formula: where Пб is the rotation speed of the leading pulley of the variator 6, rpm;

[0053] P7 - rotation speed of the driven pulley of the variator 7, rpm;

[0054] 1g - gear ratio of gear pair 3 and 5. Determined by the following formula:

[0055] Z5

[0056] 1 2 ~ _ > ' Z3 z5 - number of teeth of gear wheel 5. i4 - gear ratio of single-stage reducer. Determined by the formula:

[0057] Z14 - number of gear teeth 14;

[0058] Z15 — number of teeth of gear wheel 15; 9 217 - gear ratio of the planetary mechanism with the planet carrier stopped 9.

[0059] The box has the following operating modes: "Parking", "Dynamic parking", "Reverse", "Neutral position", "Forward movement".

[0060] In the “Parking” mode, the primary shaft 1 is disconnected from the first gear 3 by means of the friction-tooth clutch 2.

[0061] In the “Neutral position” mode, the leading pulley 6 of the variator is disconnected from the second gear wheel 5 by means of the clutch 16.

[0062] In the modes "Dynamic Parking", "Reverse", "Forward Movement" the gearbox operates as follows. The rotation of the primary shaft 1 through the engaged friction-toothed clutch 2 and gear 3 simultaneously causes the oppositely directed rotation of gear wheels 5 and 4. The rotation of the second gear wheel 5 is perceived by the engaged clutch 16 and the leading pulley 6 of the variator, which through the belt 8 transmits the rotation to the driven pulley of the variator 7. The driven pulley 7 transmits the rotation to the epicycle 17. The rotation of the first gear wheel 4 is perceived by the planet carrier 9, which transmits the diametrical rotation to the axes of the satellites 10 and the satellites 12.

[0063] In the "Dynamic Parking" mode, the rotating satellites 11, which simultaneously engage with the epicycle 17 and the sun gear 12, do not cause the sun gear 12 to rotate, i.e. the rotation speed of the third gear wheel 15 is zero ni5=0. This is explained by the fact that the ratio of the rotation speeds of the epicycle 17 and the planet carrier 9 is maintained, at which the following equality of the variator operation is observed:

[0064] ■ — *3

[0065] 11 1 i2 I UT 1 1 7 2 eh

[0066] In this case, the variator belt (Fig. 2) is in a certain middle position of its adjustment range, which is calculated based on the chain of gear ratios of the entire gearbox design. Thus, in the "Dynamic Parking" mode, the rotation speed of the output link of the gear wheel 15 has a zero value, which means that a torque converter is not required in this design of the gearbox.

[0067] In the "Reverse" mode, the simultaneously engaging satellites 11 with the epicycle 17 and the sun gear 12 cause the oppositely directed rotation of the sun gear 12, shaft 13 and gear 14. Gear 14 causes the oppositely directed rotation of gear wheel 15, which does not coincide with the direction of rotation of the primary shaft 1. This is explained by the fact that the ratio of the rotation speeds of the epicycle 17 and the planet carrier 9 is maintained, at which the following condition of the variator operation is met:

[0068] The equal sign means that the "Reverse" mode has a gear speed range of 15, which includes the zero value ni5=0.

[0069] In the "Reverse" mode, the variator operates to accelerate (Fig. 3), the higher the rotation speed of the driven pulley 7, the greater the negative, relative to the primary shaft 1, rotation speed of the output link of the gear wheel 15. Thus, for the operation of the gearbox in the "Reverse" mode, a package (gear block) of the front and rear gears is not required.

[0070] In the "Forward movement" mode, the simultaneously engaging epicycle 17 and sun gear 12 rotating satellites I cause the coincident rotation of sun gear 12, shaft 13 and gear 14. Gear 14 causes the oppositely directed rotation of gear wheel 15, which coincides with the direction of rotation of primary shaft 1. This is explained by the fact that the ratio of rotation speeds of epicycle 17 and planet carrier 9 is maintained, at which the following condition of variator operation is observed:

[0071] The equal sign means that the Forward mode has a gear speed range of 15, which includes the zero value ni5=0.

[0072] In the "Forward Movement" mode, the variator operates in deceleration (Fig. 4), the lower the rotation speed of the driven pulley 7, the higher, relative to the primary shaft 1, the rotation speed of the output link of the gear wheel 15. Thus, for the operation of the gearbox in the "Forward Movement" mode, a package (gear block) of the front and reverse gears is not required.

[0073] The friction-tooth clutch 2 is designed to disconnect the rotating primary shaft 1 from the gear 3 when the gearbox is operating in the "Parking" mode and to smoothly connect the rotating primary shaft 1 with the gear 3 when the gearbox is operating in the "Dynamic Parking" mode. The clutch 16 is designed to protect the variator from overload when the gearbox is operating in the "Dynamic Parking" mode in the event that the following condition is not met:

[0074] 11 7 2 9

[0075] An example of calculating the rotation speed of gear wheel 15 when the gearbox is operating in the “Dynamic Parking”, “Reverse”, and “Forward” modes.

[0076] To calculate the rotation speed of gear wheel Щ5, the following values ​​are taken: i = l ,1 i3-l ,3 14=4.5 uT 217 =o,3, variator control range D=2.81.

[0077] When the gearbox is operating in the “Dynamic Parking” mode, the rotation speed of the primary shaft 1 is taken as П]=700...3500 rpm and more.

[0078] Subject to the condition:

[0079] •

[0080] 11 1 1 7 2 9 we get ii=0.9091, ni5=0 rpm.

[0081] When the gearbox is operating in the “Reverse” mode, the rotation speed of the primary shaft 1 is taken to be = 700... 1500 rpm.

[0082] Subject to the condition: and limiting the range of variator control we get i]=0, 9091...0.7, pp=0...- 476 rpm.

[0083] When the gearbox is operating in the “Forward Movement” mode, the rotation speed of the primary shaft 1 is taken as ni=700...3500 rpm.

[0084] Observing the condition and limiting the variator control range we get ii=0.9091..2.77, П15=0... 1656.6 rpm.

[0085] When determining the vehicle speed using the formula V=0.19Dnis (km / h), where the wheel diameter D=0.7M (tire 225 / 55R18), we obtain the following values:

[0086] The torque of Mi 5 on the output link of gear wheel 15 in the modes “Reverse movement”, “Forward movement” is determined by the formula:

[0087] M]5=MiU K where: Mi is the torque on the primary shaft 1, equal to the torque of the internal combustion engine; Uk is the gear ratio of the box. j t t > M и 12 17 to U и 1 1 7 2 9 _ 1 1 of 2

[0088] The increase in the operating mileage by 50% is achieved by the fact that the torque received by the primary shaft 1 from the internal combustion engine (ICE) is divided by gear 3 and gear wheels 4 and 5 into two equal parallel flows, one of which rotates the planet carrier 9, and the second through the variator epicycle 17. As a result, we obtain that the variator perceives 50% of the ICE torque. Taking into account the gear ratio 1g, the variator torque Mv when the gearbox is operating in the "Reverse" and "Forward" modes is determined by the formula:

[0089] M B =0.5Mii2

[0090] Thus, we accept that belt stretching, belt wear and the working surfaces of the variator pulleys over a period of operation equal to the period of operation of the prototype are reduced by half and we establish that for a gearbox with a built-in variator, designed for maximum torque, like the prototype, when using materials with the same wear-resistant and strength characteristics of the gearbox, the operating mileage will increase by 50% to 300...320 thousand km.

Claims

Invention formula A continuously variable transmission comprising a primary shaft, a variator consisting of a driving pulley and a driven pulley connected by a belt, a three-link planetary mechanism consisting of a planet carrier with satellites, an epicycle and a sun gear, and an output shaft, characterized in that it additionally includes a friction-tooth clutch which is configured to connect and disconnect the primary shaft and the first gear connected to the first and second gear wheels, a toothed clutch which is configured to connect and disconnect the driving pulley of said variator and the second gear wheel, wherein the first gear wheel is connected to the planet carrier of said planetary mechanism, wherein the epicycle of said planetary mechanism is connected to the driven pulley of said variator, and the satellites of said planetary mechanism are connected to the sun gear which is connected to the sequentially connected output shaft, the second gear wheel and the third gear.

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